I installed a new convertible jet pump in my basement today. It's the type with two pipes. It is the same type/HP(3/4)as the one I had before. After installation was complete I primed the pump. I took the top cap off, filled it with water, replaced cap and powered the pump. It took many tries but it is now building pressure(close to 40 PSI) but doesn't make it all the way. When I shut the power off it holds at 20PSI yet no water is available in the house. Opening the valve at the pressure tank doesn't relieve the pressure. Only when I take the top cap off again the pressure is released. I am at my wits end. Any help?

I should add the only difference in the install was that on the old pump the small pipe to the pressure switch came out of the cast iron base of the pump. The recommended setup for this pump was to use a provided pressure regulator on top of the unit and run the small pipe from the to the pressure switch.

The recommended setup for this pump was to use a provided pressure regulator on top of the unit and run the small pipe from the to the pressure switch.

Not too sure what you mean by that. There is a pressure regulator AND a pressure switch.

Whatever the cut in pressure is, set your tank pressure 2# below that. So, for example, if the pump cuts on at 30#, then set your tank pressure to 28#. Do this with the power off and pressure drained to zero by opening a low-level faucet.